It has long been known that heat treatments can be used to improve the properties of materials. More recently it has been found that cold treating of many materials can similarly be used to improve the materials. of particular interest has been treatments that involve cooling a workpiece to cryogenic temperatures, for example temperatures of about -300 degrees Fahrenheit that can be readily achieved by the use of liquid nitrogen as the coolant.
Generally these treatments involve both gradual cooling at a controlled rate followed by gradual heating at a controlled rate to room temperature or higher. The improvement in the materials treated is generally explained to result from the rearrangement, such as denser packing, of molecules in the material and the improved properties have primarily involved the mechanical strength or electrical conductivity of the materials.